GI Surgery Peri-Operative Care

Question 1

describe shock stabilization of surgical GI patients

Answer 1

mostly hypovolemic, obstructive, and/or distributive = all same underlying mechanism of decreased preload, so treat by increasing preload

1. resuscitation:
   -IV fluids
   - +/- pressors
   -WHILE you ID and treat underlying disease (determine if medical or surgical)

Question 2

describe shock resuscitation

Answer 2

1. fluid bolus (need a catheter)
   -isotonic crystalloid
   –SA: 10ml/kg increments over 10-15 min
   –LA: 20 mg/kg increments as fast as possible

-consider small volume of volume expanders followed by isotonic crystalloid bolus (hypertonic saline, synthetic colloids) to increase perfusion as you stabilize by holding that fluid in the intravascular space

-REASSESS parameters before repeat

2. +/- colloid
   -natural is better! there are no formulations for rapid administration in LA though :(
3. +/- vasopressors

Question 3

what are the goals of stabilization in terms of volume and electrolytes?

Answer 3

1. intravascular volume status goals:
   -normotension and euvolemia
   -assess via: vital parameters, blood pressure, lactate
2. interstitial volume status: ideally would improve hydration but cannot wait until euhydrated for emergency surgery
3. correction of electrolytes:
   -postassium, calcium: LA
   -chloride (consider NaCl)

Question 4

what concurrent problems might emergent SA GI patients also present with and how to correct?

Answer 4

1. dextrose: give IV if hypoglycemic
   -generally secondary to secondary peritonitis (GI perf)
   -0.5mg/kg IV as bolus, need to add to IVF after initial bolus because 1 dose is rarely enough
2. antibiotics: admin IV pre-op if high suspicion for sepsis
   -regardless of etiology (medical or surgical)
3. anti-arrhythmics:
   -ventricular arrhythmias most common arrhythmia in dogs secondary to intra-abdominal disease
   -but does NOT mean there is underlying cardiac issue!

Question 5

what concurrent problems might LA GI patients present with and how to correct?

Answer 5

1. acid base:
   -acidosis: generally related to poor perfusion and increased lactate, so resuscitate bolus
   -contribution of abdominal distension: rumen tube, trocharization, surgery! (trochar better for cows than horses)
2. ketosis:
   -dextrose supplementation
   -once GI tract functional, propylene glycol, transfaunation
3. cardiac: if you see a horse in V-tach is likely IS a primary disease that you need to treat! (unlike SA)

Question 6

describe endotoxemia treatment

Answer 6

1. bind endotoxin:
   -GI tract: di-tri-octahedral smectite or activated charcoal
   -blood: hyperimmune plasma, hyperimmune serum, polymixin B, phospholipid emulsion
2. inflammatory response:
   -NSAIDs
   -pentoxyfilline
   -ethyl pyruvate
   - +/- DMSO or lidocaine
3. remove source:
   -R&A
   -enterotomy
4. prevent complications:
   -laminitis: ice boots

Question 7

describe SA pre-op analgesia

Answer 7

1. opioids: should be first line!
   -pure mu agonist: hydromorphone, methadone, fentanyl (CRI if right to sx, short acting and reversible)

-partial mu agonist: buprenorphine

-butorphenol is NOT an analgesic!

2. adjunct therapies: should not be solo agents
   -NMDA receptor antagonist: ketamine
   -Na channel blocker: lidocaine

*NSAIDs NOT for use in a SA patient with GI signs!!

Question 8

describe LA pre-op analgesia

Answer 8

1. NSAIDs commonly used, esp flunixin meglumine
   -not as many issues with ulcers with short term use (unlike SA)
2. alpha 2 agonists commonly used
   -provide sedation as well
   -aid with safety of diagnostics and pain
   -most potent, so low use post-op
3. opioids:
   -horses have more side effects with pure mu agonists so are used less commonly
   -often use butorphenol (mu antag, kappa agonist): provides much less analgesia but works synergistically with alpha-2 for sedation and analgesia

Question 9

describe prophylactic antimicrobials

Answer 9

1. common use for GI sx patients!
2. decreases:
   -surgical site infections
   -postop complications
   -cost of treatment
3. guidelines
   -considerations: procedure and patient factors
   -follow recommended timing, class, and duration
4. judicious use is important!
   -risk to patient: microbiome alterations, antimicrobial associated diarrhea, more susceptible to nosocomial infections, and post op complications

-risk to others: antimicrobial resistance, healthy reservoirs, hospital and community acquired disease (salmonella equine hospital outbreaks)

Question 10

what justifies the use of prophylactic antibiotics in GI surgery?

Answer 10

1. procedure classification:
   -many procedures are clean-contaminated
   -cannot predict how nasty prior to surgery
2. infectious complications >5%
   -incisional infection complications range from 6.4-43% in horses so for sure use
3. consequences of infection impactful:
   -increase hospital duration and cost: use
   -decrease quality of recovery and survival without: use

Question 11

how to use antibiotics in GI surgery in LA?

Answer 11

1. which to choose:
   -broad spectrum (refine with C&S for infections)
   -lowest generation possible
   -know FARAD regulations for food animals
2. dose appropriately: weight and redose intra-op
3. classify surgery and discontinue as soon as possible:
   -peri-op (up to 24hr) indicated for clean and clean-contaminated procedures
   -prolonged post op course in dirty or pre-existing contamination

Question 12

describe SA antimicrobial use

Answer 12

1. early admin increases survival time
   -patients not in shock have a little bit longer (admin within 3 hours of presentation)
2. pre-op: use if sepsis possible or probable
3. intra-op: always used
4. post-op: use if sepsis possible or probable

Question 13

describe post-op monitoring

Answer 13

goals:
1. pass checklist for recovery/discharge
2. diagnose and see response to treatment for complications

what do:
1. serial PE
2. pain scoring
3. ins and outs: NG tube as needed, appetite
4. bloodwork
5. BP, ECG, pulse ox as needed

Question 14

describe LA post-op care

Answer 14

goals for discharge:
1. no colic
2. normal manure production
3. eating
4. drinking
5. off drugs

components:
1. analgesia
2. anti-inflam
3. anti-microbials
4. fluid support
5. nutrition support

Question 15

describe SA post-op care

Answer 15

goals for discharge:
1. eating
2. drinking
3. oral meds only
4. no more vom/regurg
5. pooping isn’t as important for dogs and cats! may be fine once home and comfy

considerations:
1. fluid therapy
2. enteral nutrition
3. analgesia
4. +/- abx

Question 16

describe the LA approach to refeeding

Answer 16

1. many benefits for GI recovery if done early
2. not one size fits all:
   -based on dx, procedure, and postop complications
3. ruminants: consider transfaunation to re-establish flora

Question 17

describe SA post op nutrition

Answer 17

1. enteral is best! offer food first
2. but always anticipate the need for assisted enteral nutrition
   -NGT or NET
   -E-tube
3. parenteral is an option for those unable to keep food down

Question 18

describe reflux, a postop complication in LA

Answer 18

1. due to ileus, usually SI
   -inflammation, pain, meds
   -or obstruction :(
2. in approx 20% of patients with SI lesions after surgery, generally 1st 1-3 days postop
3. prevention:
   -minimize handling
   -good surgical technique
   -lidocaine, anesthesia, anti-inflam, prokinetics as needed
4. treatment/support:
   -gastric decompresison and fluid support
   -anti-inflam
   -lidocaine
   -prokinetics: metoclopramide, erythromycin

Question 19

describe regurg, a SA postop complication

Answer 19

1. secondary to SI functional ileus: underlying GI disease, pain, opioid use
2. treatment:
   -prokinetics: metaclopramide (first line), or cisapride (second line)
   -anti-nausea meds: ondansetron
   -NGT aspiration

Question 20

describe incisional infections in LA

Answer 20

1. multifactorial
2. in 10-20% of patients, increased with re-laparatomy (increased chance for hernia formation)
3. clin signs:
   -FUO
   -pain
   -increased edema
   -drainage (after 24hr)
   -1-4 days post op
4. prevention:
   -lavage linea during closure
   -honey, abx
   -cover incision: stent, abd bandage
5. treatment:
   -open and drain
   - +/- abdominal bandage, may decrease risk of hernia
   -rarely abx

Question 21

describe incisional complications in SA

Answer 21

1. infection:
   -clin signs: redness, discharge, swelling, fever, discomfort at site
   -treatment: superficial wound care, abx
2. seroma:
   -clin signs: swelling, +/- discomfort at site
   -treatment: time and warm compresses

Question 22

describe intestinal incision dehiscence

Answer 22

1. clin signs: 3-5 days post op
   -appreciable decline
   -recurrent GI symptoms
   -fever
   -abdominal effusion
2. diagnosis: fluid cytology
3. treatment: revision surgery

Question 23

describe adhesions in LA

Answer 23

1. inflam triggers coag and fibrin formation
   =fibrinous adhesions become fibrous adhesions with time
2. in 20% of cases, SI and R&A increase chances
3. clin signs:
   -asymptomatic to severe colic
   -reflux
   - approx 5-10 days post op, less chance symptomatic after 1 year
4. prevention:
   -good sx technique
   -carboxymethylcellulose
   -lavage
   -anti-inflam
   -abx, heparin
5. treatment:
   -modify diet
   -surgical adhesiolysis